Device for cutting off the ends of weft threads



.Eufiy 24, 1951 H. BOSSHARD DEVICE FOR CUTTING OFF THE ENDS OF WEFTTHREADS Filed June 16, 1949 INVENTOR GSSHARQ HANS Patented July 24, 1951 assists DEVJICE FORYVCUTTING OFF THE ENDS .WEFT THREADS HansBosshard, Frauenfeld, Switzerland Application June 16, 1949, Serial No.99,560 In Switzerland June 22, 1948 Claims. (01. 139--3-03) Deviceswhich have long been known, associated with the stretching roller ofautomatic weaving looms, make it possible to out on or shear off theweft thread left on changing .aspool, i. e. on exchanging a shuttle.Nevertheless ends of weft thread remain at spaced intervals along theedge of the cloth, whether they are torn off or out 01f, which ends givethe. finished cloth an unsightly appearance. Before the cloth isfinished it must, therefore, be freed from these ends of weft thread.This is done in various ways, for example by burning off, which is notwithout danger, or by hand with scissors. Lately expensive andcomplicated machines have been constructed which serve this purpose butare not completely satisfactory because in this case also the machinemust be minded and the'woven cloth must be subjected to a furtherworking step, which in the last analysisis equivalent to an increase inprice or in cost of production.

It is an object of the presentinvention to remove these disadvantages.The present inven tion, therefore, relates to a device for cutting offthe end of the weft thread left on changing the spool of an automaticweaving loom with which the device is associated, characterised in thatthe end piece of the stretching roller cylinder reaches as far as thecutting plane in between the lower stationary shearing blade lying nextto the edge of the cloth and the upper mov able shearing bladeco-operating therewith, and in that the tensioning wheels of thestretching roller reach so near to the end face of the end piece thatthe edge of the cloth is guided to reach the said cutting plane. theweft thread is automatically cut off immediately at the edge of thecloth.

In this way the end of The annexed drawing shows one embodiment I by wayof example of the subject of the invention.

Fig. l is a rear elevational view.

Fig. 2 is a cross section showing the arrangement of shearing bladesadjacent the edge of the cloth taken on the line 2--2 of Fig. 1.

Fig. 3 is a side view showing the construction of a movable shearingblade spaced further away.

According to Fig. 1 the stretching roller consists in the usual way of acylinder I which is secured by means of a screw spindle 2 passingtherethrough to a frame-part 3 connected to the frame of a weaving loom.The cylinder i is provided with a series of tensioning wheels 4 whichare provided on their periphery with fine teeth or pins which areintended to engage in the cloth. These tensioning wheels 4 are disposedin the usual way as shown in Fig. 1 with the planes of their discsinclined to the axis of the securing spindle 2 and are mounted to rotatefreely about this spindle. The end of the cylinder I at the side of thecloth is formed by an end piece 5. Above the cylinder is disposed astretching roller guard 6 which is rockably mounted on the frame in theusual way and serves to guide the length of' cloth, not shown. Thelength of cloth which is thus pulled under the guard 6 over the cylinderI progressively in ac-- cordance with the-progress of the weaving isthus pressed on to the small teeth or pins of the tensioning Wheels 4and thus causes these tensioning wheels to rotate about the axis of thespindle 2 whereby the cloth is held stretched sideways and the edge ofthe cloth'is guided exactly over the cylinder l' in a line lying atright-angles to the axis of the cylinder.

According to the present invention the tensioning wheels 4 reach so nearto the end face 7 of the end piece 5 that the edge of the cloth isguided to reach as far as the plane of this end face I. At the same timethe said end face 1 lies in the cutting plane of the pair of shearingblades nearest to the edge of the cloth. This pair consists of the lowerstationary shearing blade 8 and the upper, vertically movable blade 9,so that the end piece 5 reaches as far as the stationary shearing blade8. The arrangement of the said shearing blades 8 and 9 canbe seenclearlyfrom Fig. 2. The shearing blade 9 is carried in the usual way by aholder H] which is rockably mounted about an axle I I fixed to the frameand parallel to the axis of the spindle 2 and is provided with a leverarm l2 directed obliquely downwards which is caused to move to and froby any desired means as shown by the double arrow I 3. This movement ismost simply derived from the lay of the weaving loom which swingsperiodically forwards and backwards with a quick return motion. As maybe seen from Fig. 2, the movable shearing blade 9 is cut out i in sickleform on the side directed towards the end piece 5 of the cylinder sothat it can swing past the end piece 5 of the cylinder unhindered. As aresult the edge of the cloth is pressed downwards by the roller marginof the guard B so strongly that it runs immediately above the shearingedge '1. Consequently ends of weft thread projecting from the edge ofthe cloth come directly on to the shearing edge 'I' where they aresheared off by the co-operating lower edge of the movable shearing blade9.

As shown in Fig. 1 there are also two further pairs of shearing bladesspaced further from the 'edge of the cloth consisting of the stationaryshearing blades [5 and the movable shearing blades 16. As shown in Fig.3 the last-mentioned movable shearing blades Hi are provided with loweredges I5 so short that they do not suffice to shear off the weft thread.These pairs of shearing blades [5, H3 at the most need come into actionin the'event of a failure of the first pair of shearing blades 8, 9 andmay, therefore, if desired be provided with shearing edges ofappropriate lengths.

As may be seen from the foregoing, during the weaving operation themovable shearing blades carry out shearing movements uninterruptedly inrapid sequence, for example corresponding to the shuttle movement sothat every projecting weft thread is cut off with certainty close to theedge of the cloth. In order to return the movable shearing blades aspring can also be used which is strong enough to separate the bladesfrom one another even when this is rendered difficult by a thread beingclamped therebetween. When using such a spring the bell-crank lever 12need only be driven positively in one direction, for example by the laymovement, i. e. only to the right as shown in Fig. 2.

What I claim is:

1. In a device for cutting off the end of the Weft thread left onchanging the spool of an automatic weaving loom with which said deviceis associated, at least one stationary shearing blade and co=cperatingtherewith a movable. upper shearing blade, said upper shearing bladebeing controlled by a periodically oscillating member of said loom, astretching roller cylinder provided with a series of tensioning wheelsengaging the length of cloth from below and having an end piece arrangedwith its end face reaching to the cutting plane of said pair of shearingblades and the said tensioning wheels being arranged to reach so near tothe said end face of the end piece that the edge of the cloth lies inthe cutting plane of the pair of shearing blades.

2. In a device according to claim 1, said movable shearing blade beingcut out in sickle shape on a side facing the said end piece of thecylinder.

3. In a device according to claim 1, in which a guard is provided forsaid stretching roller reaching as far as said movable shearing blade.

4. In a device according to claim 1, in which a guard is provided forsaid stretching roller reaching downwards to the level, of the shearingedge of said stationary shearing blade.

5. In a device for cutting off the end of the weft thread left onchanging the spool of an automatic weaving loom with which said deviceis associated, at least one stationary shearing blade and co-operatingtherewith a movable upper shearing blade, said upper shearing bladebeing controlled by a periodically oscillating member of said loom, astretching roller cylinder providedwith a series of tensioning wheelsengaging the length of cloth from below and an end piece arranged withits end face reaching to the cutting plane of said pair of shearingblades, and the said tensioning wheels. being arranged to reach so nearto the said end face of the end piece that the edge of the cloth liesin, the said cutting plane of the pair of shearing blades, and furtherpairs of shearing blades spaced from said first-mentioned pair ofshearing. blades, the lower edges of the movable blades of said. furtherpairs of blades being so short that they do not suffice to shear theweft thread.

HANS BOSSHARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,157,397 Imbach Oct. 19, 1915FOREIGN PATENTS Number Country Date 182,366 Switzerland Feb. 15, 1936626,046 Germany Oct. 14, 1934 685,575 France Apr. 1, 1930

